In the present case, the stereotypical interpretation is intuitively blocked for the cumbersome form (4) by the cheaper alternative expression (3).
And this equilibrium encodes Horn's division of pragmatic labor: the unmarked (and lighter) message fu expresses the stereotypical interpretation tst, while the non-stereotypical state t¬st is expressed by the marked and costlier message fm.
If according to the second heuristic an unmarked utterance gives rise to a stereotypical interpretation, now we have that this interpretation is overruled if a marked utterance is produced.
Thus, in terms of his notion of strong optimality, i.e., optimality for both speaker and hearer, Blutner can account for the intuition that sentences typically get the most plausible, or stereotypical, interpretation.
The reason is that on the assumption that (4) has the same semantic meaning as (3), the stereotypical interpretation would be hearer-optimal not only for (3), but also for (4).
Because (3) is less complex than (4), and ist is the more stereotypical interpretation compatible with the semantic meaning of (3), it is predicted that (3) is interpreted as ist.
Blutner proposed that ⟨f,i′⟩ > ⟨f,i⟩ iff i′ is a more likely, or stereotypical, interpretation of f than i is: P(i′ | ⟦ f ⟧) > P(i | ⟦ f ⟧) (where ⟦ f ⟧ denotes the semantic meaning of f, and P(B | A) the conditional probability of B given A, defined as P(A∩B /P(A)).
As a result, the marked (4) will get the on-stereotypical interpretation.
Take ist to be the more plausible interpretation where John killed the sheriff in the stereotypical way, while i¬st is the interpretation where John caused the sheriff's death in an unusual way.
